Real-time sound source orientation estimation using a 96 channel microphone array

This paper proposes real-time sound source orientation estimation based on orientation-extended amplitude beamforming (OE-ABF). To recognize a sound source orientation (such as face orientation) is an important function for a robot who can achieve natural human-robot interaction because the function is required to distinguish the human target from a robot or another person. We developed a sound source orientation system using orientation-extended beamforming (OE-BF) and showed the system worked properly at least under a specific controlled environment. However, in practical use, this system does not work properly because the system doesn´t take into account the differences between the supposed model in OE-BF and in practical situations. For example, the system model supposes that there is neither noise nor reverberation, however, this is not a realistic assumption. To solve this assumption mismatch problem, we propose sound source orientation estimation based on OE-ABF, and constructed a real-time sound source orientation estimation system with the proposed method using a 96 ch microphone array. Evaluation results of our proposed system show that the average error of estimated angles is lower than 5°, while the error of our previously reported system was greater than 20°. With this system, the robot is able to distinguish that the utterance target of a person standing 1 m in front is itself or another person standing 0.2 m to the left of the robot. This is valuable for human-robot interaction.